When a fire burns with high intensity, soot deposited on nearby surfaces is burned off, leaving a clean area. Such an area of clean burn was present on the bottom of the cable tray directly above and slightly inboard of port generator valve covers 1 and 2. The localized nature of the fire indicates that the most intense fire was centred in this area, which is also the general location of the fuel filters. The vertical soot patterns on the exhaust uptake, the horizontal patterns on top of valve covers 4, 5 and 6, and the shadowing on the aft surfaces of the same valve covers, indicate a fire origin at the engine's port side, forward of cylinder head No. 1. The most probable high temperature ignition sources in this area are the indicator cock protruding from the cylinder head and the uncovered exhaust manifold connecting to the turbocharger. Three sources of fuel were present in the vicinity of cylinder head No. 6. Lubricating oil was present beneath the valve cover. However, it was not under pressure and was contained by the cover itself. As the covers were intact and in place subsequent to the fire, lube oil can be ruled out as a source of fuel. The two fuel oil filters mounted on the starboard upper side of the engine contain fuel under pressure of approximately one bar and are mounted on the same plane as the exposed exhaust manifold and indicator cock. Examination of the fuel filters indicated that the aft filter was extensively damaged internally. This indicates that the aft filter was not cooled by fuel flow and thus not in service at the time of the occurrence. It can, therefore, be ruled out as a source of fuel to the fire. Furthermore, the position of the fuel selector cock indicated that the forward filter was in service at the time of the occurrence. At an unknown time before the occurrence, modifications had been made to the forward filter cover/bolt sealing surface, which removed the seating groove for the copper washer and left the sealing surface uneven and grooved with file marks. As a result, the watchkeeping engineer had experienced a problem obtaining a fuel-tight joint at the copper gasket sealing the cover to its securing bolt when he serviced the filter one hour before the fire. No new copper gaskets were available on board, so the existing copper gasket was annealed and re-used. Once a copper gasket has been deformed by use, it is more difficult to obtain a tight seal for subsequent usage even if it has been annealed. The combination of the modified, uneven sealing surface and the re-use of the used gasket increased the risk of leakage once pressure was applied to the filter. Under normal circumstances a liquid fuel would have to be above its flash point for vapours to form an ignitable mixture. However, in the case of spraying fuel, ignition can often occur at temperatures below the flash point provided a heat source above its ignition temperature is present. Therefore, the initial leak developed at the copper gasket and, due to the mounting position of the filter and lack of shielding between it and the engine, sprayed a fine mist of fuel onto the exposed indicator cock or exhaust manifold, both of which were above the ignition temperature of the fuel. As the fire progressed, it melted the main cover rubber O-ring on the forward filter, which then provided a large volume of pressurized fuel until the fire was discovered and the engine was shut down. It is a common practice on merchant ships for the chief engineer to take over the engine-room watch during fire and emergency drills. This practice ensures continuity of watchkeeping during the drill and expeditious provision of emergency services (pumping, emergency power, electrical isolation) required by the emergency or drill. During the drill, the chief engineer and mechanical assistant remained in the control room, the location of which does not provide a view of the port side of the engine-room including the port generator. Neither the chief engineer nor the mechanical assistant on watch had made a visual inspection of the engine-room between 1515 and 1600. As a result, the fire was able to establish itself well before being discovered. Vessels built after 1 September 1984 are required to have the wiring for their duplicated steering power and control systems follow routes as widely separated as possible. This ensures that no single point damage can render the system completely inoperable. However, the NANTICOKE was built in 1980, before the new international regulations came into effect; the steering pump main power cables and the control wiring from the bridge ran together in a common cable tray past the port generator. Even though the fire was restricted to the area immediately surrounding the front of the port generator, routing the common cable tray that contained all of the steering systems resulted in the cables being destroyed. After the fire was extinguished, attempts were made to get the vessel underway to New York. However, due to fire damage to the wiring, no steering was available. This effectively disabled the vessel until an alternate source of electrical power was jury-rigged to the steering gear.Analysis When a fire burns with high intensity, soot deposited on nearby surfaces is burned off, leaving a clean area. Such an area of clean burn was present on the bottom of the cable tray directly above and slightly inboard of port generator valve covers 1 and 2. The localized nature of the fire indicates that the most intense fire was centred in this area, which is also the general location of the fuel filters. The vertical soot patterns on the exhaust uptake, the horizontal patterns on top of valve covers 4, 5 and 6, and the shadowing on the aft surfaces of the same valve covers, indicate a fire origin at the engine's port side, forward of cylinder head No. 1. The most probable high temperature ignition sources in this area are the indicator cock protruding from the cylinder head and the uncovered exhaust manifold connecting to the turbocharger. Three sources of fuel were present in the vicinity of cylinder head No. 6. Lubricating oil was present beneath the valve cover. However, it was not under pressure and was contained by the cover itself. As the covers were intact and in place subsequent to the fire, lube oil can be ruled out as a source of fuel. The two fuel oil filters mounted on the starboard upper side of the engine contain fuel under pressure of approximately one bar and are mounted on the same plane as the exposed exhaust manifold and indicator cock. Examination of the fuel filters indicated that the aft filter was extensively damaged internally. This indicates that the aft filter was not cooled by fuel flow and thus not in service at the time of the occurrence. It can, therefore, be ruled out as a source of fuel to the fire. Furthermore, the position of the fuel selector cock indicated that the forward filter was in service at the time of the occurrence. At an unknown time before the occurrence, modifications had been made to the forward filter cover/bolt sealing surface, which removed the seating groove for the copper washer and left the sealing surface uneven and grooved with file marks. As a result, the watchkeeping engineer had experienced a problem obtaining a fuel-tight joint at the copper gasket sealing the cover to its securing bolt when he serviced the filter one hour before the fire. No new copper gaskets were available on board, so the existing copper gasket was annealed and re-used. Once a copper gasket has been deformed by use, it is more difficult to obtain a tight seal for subsequent usage even if it has been annealed. The combination of the modified, uneven sealing surface and the re-use of the used gasket increased the risk of leakage once pressure was applied to the filter. Under normal circumstances a liquid fuel would have to be above its flash point for vapours to form an ignitable mixture. However, in the case of spraying fuel, ignition can often occur at temperatures below the flash point provided a heat source above its ignition temperature is present. Therefore, the initial leak developed at the copper gasket and, due to the mounting position of the filter and lack of shielding between it and the engine, sprayed a fine mist of fuel onto the exposed indicator cock or exhaust manifold, both of which were above the ignition temperature of the fuel. As the fire progressed, it melted the main cover rubber O-ring on the forward filter, which then provided a large volume of pressurized fuel until the fire was discovered and the engine was shut down. It is a common practice on merchant ships for the chief engineer to take over the engine-room watch during fire and emergency drills. This practice ensures continuity of watchkeeping during the drill and expeditious provision of emergency services (pumping, emergency power, electrical isolation) required by the emergency or drill. During the drill, the chief engineer and mechanical assistant remained in the control room, the location of which does not provide a view of the port side of the engine-room including the port generator. Neither the chief engineer nor the mechanical assistant on watch had made a visual inspection of the engine-room between 1515 and 1600. As a result, the fire was able to establish itself well before being discovered. Vessels built after 1 September 1984 are required to have the wiring for their duplicated steering power and control systems follow routes as widely separated as possible. This ensures that no single point damage can render the system completely inoperable. However, the NANTICOKE was built in 1980, before the new international regulations came into effect; the steering pump main power cables and the control wiring from the bridge ran together in a common cable tray past the port generator. Even though the fire was restricted to the area immediately surrounding the front of the port generator, routing the common cable tray that contained all of the steering systems resulted in the cables being destroyed. After the fire was extinguished, attempts were made to get the vessel underway to New York. However, due to fire damage to the wiring, no steering was available. This effectively disabled the vessel until an alternate source of electrical power was jury-rigged to the steering gear. The bolt sealing surface on the forward fuel filter cover (port generator) had earlier been modified by removing the recess used to seat the copper washer. The surface was uneven and marred by file marks. When the filter was serviced an hour before the fire, the copper washer was not renewed, as a spare was not available. The port generator forward fuel filter was in service at the time of the fire. The location of the forward fuel filter allowed leaking fuel to contact an adjacent, unshielded hot exhaust manifold and indicator cock. No inspection rounds of the engine-room were made between 1515 and 1600, the time at which the fire was discovered. Vessels built before 1 September 1984 were not required to have wiring for duplicated steering power and control systems in separated cable runs. The fire extensively damaged the main power and control wiring for the vessel's duplicated steering systems, which ran together in a common cable tray above the generator.Findings The bolt sealing surface on the forward fuel filter cover (port generator) had earlier been modified by removing the recess used to seat the copper washer. The surface was uneven and marred by file marks. When the filter was serviced an hour before the fire, the copper washer was not renewed, as a spare was not available. The port generator forward fuel filter was in service at the time of the fire. The location of the forward fuel filter allowed leaking fuel to contact an adjacent, unshielded hot exhaust manifold and indicator cock. No inspection rounds of the engine-room were made between 1515 and 1600, the time at which the fire was discovered. Vessels built before 1 September 1984 were not required to have wiring for duplicated steering power and control systems in separated cable runs. The fire extensively damaged the main power and control wiring for the vessel's duplicated steering systems, which ran together in a common cable tray above the generator. The fire was caused by a leakage of fuel, which contacted an exposed exhaust manifold, from the forward fuel filter on the port generator. Contributing to the occurrence was the modification to the fuel filter cover, the re-use of the copper sealing gasket on the cover, the unshielded hot exhaust surfaces adjacent to the filter, and the less-than-adequate engine-room watchkeeping duty during the fire drill before the occurrence.Causes and Contributing Factors The fire was caused by a leakage of fuel, which contacted an exposed exhaust manifold, from the forward fuel filter on the port generator. Contributing to the occurrence was the modification to the fuel filter cover, the re-use of the copper sealing gasket on the cover, the unshielded hot exhaust surfaces adjacent to the filter, and the less-than-adequate engine-room watchkeeping duty during the fire drill before the occurrence. Safety Action Safety Action by the Vessel's Owners Notwithstanding that the NANTICOKE is the only vessel in the owners fleet with this model of generator, the owners have taken the following measures to prevent a recurrence: New top covers have been installed on all generator fuel filters. Metal shields have been installed between filters and adjacent hot exhaust surfaces to prevent contact in the event of filter leakage. The steering control and power wiring have been re-routed so that they do not pass over the generators' forward ends. An internal safety bulletin has been circulated to the entire fleet apprising them of the occurrence. Safety Action Taken by the TSB Marine Safety Advisory (MSA) 06/99 was sent to Transport Canada, Marine Safety (TCMS) indicating that, since 1 July 1999, four engine-room fires have occurred on board Canadian ships resulting from oil being exposed to hot exhaust surfaces. Although TCMS had previously issued information with respect to such occurrences (Ship Safety Bulletin 13/85), the risk of serious engine-room fires continues. Therefore, MSA 06/99 suggested that TCMS may wish to take additional measures to remind owners and operators of the dangers associated with combustible liquids near hot surfaces, and the importance of maintaining fuel/lube-oil and exhaust shielding/lagging in optimum condition. In response, in June 2000 TCMS issued Ship Safety Bulletin 8/2000 to the industry. The bulletin addresses the potential dangers that exist when equipment, (in particular fuel system components) is modified from its original configuration/specifications without the advice of the manufacturer or consideration of the hazards that may result from such modifications. Safety Action Taken by Acomarit Canada Ltd. Subsequent to the occurrence, Acomarit Canada Ltd., the ship management company that is contracted to manage the Canada Steamship Lines fleet, circulated a letter to all chief engineers within the fleet stressing the importance of frequent engine-room rounds, including during drills.